1. Field of the Invention
The present invention relates to an exposure apparatus, more particularly to an exposure apparatus which is used during manufacturing semiconductor devices, liquid crystal display devices and the like in a lithography step and to an exposing method.
2. Related Background Art
A projection exposure apparatus has been used, which projects patterns of a photomask and a reticle (hereinafter referred to as a reticle) under exposure light onto a photosensitive substrate via a projection optical system during manufacturing semiconductor devices, liquid crystal display devices. U.S. Pat. No. 5,477,304 disclosed an exposure apparatus capable of performing an accurate exposure with the combination of a coarse motion stage and a fine motion stage for a reticle. Further, U.S. Pat. No. 5,172,160 discloses an exposure apparatus having a device capable of suppressing a vibration of the apparatus.
However, in the foregoing conventional exposure apparatuses, it is difficult to sufficiently suppress a faulty exposure due to vibrations of the exposure apparatus boy.
From the view point of the above described circumferences, the object of the present invention is to provide an exposure apparatus which is capable of suppressing an occurrence of a faulty exposure due to vibrations of the exposure apparatus body and performing a high accuracy exposure.
It is an object of the present invention to provide an exposure apparatus for projecting an image pattern on a mask onto a photosensitive substrate, the apparatus comprising: a body; a first stage movable to the body and adapted to mount the mask; a second stage movable to the body and adapted to mount the photosensitive substrate; a measuring device for measuring the position of either of the mask mounted on the first stage or the photosensitive substrate mounted on the second stage; a vibration sensor for measuring vibration of the body; and a position controller for controlling the position of either the mask mounted on the first stage or the photosensitive substrate mounted on the second stage based on a measurement value of the vibration sensor and a measurement value of the measuring device.
According to the exposure apparatus of the present invention, the position of either the mask or the photosensitive substrate is directly measured by the measuring means, and the vibrations of the portion in the exposure apparatus body as well as the portion other than that of either the mask or the photosensitive substrate is measured by the vibration sensor. Then, the position control system controls the position of either the mask or the photosensitive substrate based on the measurement values of the vibration sensor and the measuring means.
According to the present invention, when the vibrations are caused in the exposure apparatus body, the vibrations are measured by the vibration sensor, and the errors caused in the measurement values of the measuring means are corrected by the position control system using the measurement results, whereby the position deviation between the mask and the photosensitive substrate due to the vibrations is prevented, resulting in the suppression of the occurrence of the faulty exposure.
Moreover, various kinds of the vibration sensors that can be used in the invention are taken into consideration. It is sufficient that the foregoing vibration sensor may be an acceleration meter. Since the vibrations can be directly measured by the acceleration meter, the vibrations can be measured more precisely. As another vibration sensor, if the vibration sensor is placed at a position where it is not influenced by the vibrations of the apparatus body, the vibration sensor may be constituted by combining it with a displacement sensor such as a laser interference meter and a circuit to differentiate the measurement values of the displacement sensor twice. It is another object of the present invention to provide a method of projecting a pattern image on a mask on to a photosensitive substrate, using an exposure apparatus comprising a a body with projection optical system for projecting the pattern on the photosensitive substrate; a first stage movable to the body and adapted to mount the mask; and a second stage movable to the body and adapted to mount the photosensitive substrate, the method comprising the steps of: mounting the mask on the first stage; mounting the photosensitive substrate on the second stage; directly measuring the position of either one of the mask and the photosensitive substrate to provide a first data; measuring vibrations of the body, using a vibrator attached to the body, to a second data; and controlling either one of the mask and the photosensitive substrate based on the first data and the second data to prerform the projective exposure.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.